Armature without disc carrier



R. P. BURR June 17, 1969 ARMATURE WITHOUT DISC CARRIER ofS Sheet Filed May 9, 1966 FIG.I

INVENTOR. ROBERT P. BURR BY K WW 1% A T TORNEYS.

ARMATURE WITHOUT DISC CARRIER Filed May 9. 1966 F I G 4 INVENTOR.

ROBERT P. BURR June 17, 1969 1 R 3,450,909

ARMATURE WITHOUT DISC CARRIER Filed May 9, 1966 Sheet 3 of 5 FIGS INVENTOR. ROBERT F. au/ PR A TTORWE Y3.

United States Patent 3,450,909 ARMATURE WITHOUT DISC CARRIER Robert Page Burr, Huntington, N.Y., assignor to Printed Motors, Inc., New York, N.Y., a corporation of Delaware Filed May 9, 1966, Ser. No. 554,262 Int. Cl. H02k 1/32 U.S. Cl. 310-58 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to disc type armatures for electrical machines and more particularly to such armatures not including a support disc or carrier for the windings. The invention also relates to methods of making a disc type armature not including a carrier.

When disc armatures are manufactured by a chemical process, i.e., printing circuit techniques, the conductors for the windings are formed on a dielectrical support disc or carrier either by depositing copper conductors thereon or by etching away the surplus copper from a copper coating. When disc type armatures are made by other tech niques, the individual conductors or winding segments are likewise mounted on a dielectric carrier. The carrier inhibits efficient cooling of the conductors and adds mass to the armature which increases the inertia. Also, the dielectric carrier material normally has a coefficient of expansion different from the copper winding segments and therefore the armature is subject to substantial mechanical stress and tends to warp when heated to operating tem peratures.

It is an object of this invention to provide a disc armature for an electrical machine which overcomes many of the difliculties experienced in the prior machines.

Another object is to provide an armature winding which does not include a dielectric winding support or carrier.

Another object is to provide a disc type armature with improved cooling and lower sensitivity to changing temperature conditions.

Still another object is to provide an armature with a particularly low mass.

Another object is to provide methods of making a disc type armature without a carrier or winding support.

The disc type armature in accordance with this invention includes at least two arrays of winding segments lying in adjacent parallel planes. The ends of the individual winding segments are electrically interconnected to provide successive armature turns of a closed armature winding. The winding segments in one of the arrays are insulated from winding segments in the adjacent array at their respective intersections and may be physically bonded at these intersections to provide additional structural integrity. Since there is no carrier or winding support, and since the segments are only insulated and bonded at their intersections, ventilating passages are formed passing through the armature between the winding segments.

A disc type armature can conveniently be made using two or more stampings each including an annular array of winding segments. The stampings are coated with a dielectric material and bonded at the intersections if desired. As an alternative, the winding segments can joined at their intersections by an adhesive including solld particle spacers to thereby eliminate the coating step. Thereafter, the winding segments are interconnected by joining the inner and outer ends to form a contlnuous armature winding with ventilating passages therein.

The foregoing and other objects will become apparent from the following specification which sets forth several illustrative embodiments of the invention. While the invention is described particularly with respect to electrical motors it also finds application in generators and other electrical equipment. The drawings form part oft he specification wherein:

FIGURE 1 is a plan View illustrating the metal stamping used to form the winding segment arrays for the armature;

FIGURE 2 is a perspective assembly diagram illustrating the manner in which two such stampings are assembled to form an armature unit;

FIGURE 3 is a plan view with portions broken away illustrating the armature unit after the center has been blanked and the inner bridging connections completed;

FIGURE 4 is a plan view with portions broken away illustrating the armature unit after surrounding excess material has been removed and the outer bridging connections completed;

FIGURES 4A and 4B are enlarged partial plan and cross sectional views, respectively, of the completed armature structure; and

FIGURE 5 is a cross sectional view of a completed disc type motor including the armature constructed in accordance with FIGURES 1-4.

The armature in a disc type machine includes a large number of generally radially extending winding segments distributed evenly about an annular area that will be adjacent the magnetic pole faces in the completed machine. These winding segments are interconnected to form a continuous closed armature winding. Successive winding segments are displaced by distance approximately equal to the distance between adjacent pole centers of the associated magnetic structure and are interconnected so that current flow is in one direction across the north magnetic poles and in the opposite direction across the south magnetic poles.

The armature constructed in accordance with this invention includes radially extending winding segments arranged in at least twoparallel arrays which are conveniently formed by means of metal stampings, such as shown in FIGURE 1. The stampings can be formed in a single stamping operation, or by a notching operation wherein the metal sheet is indexed and the metal between adjacent winding segments is stamped out in successive operations. Each of the winding segments in the completed stamping includes an inner tab 10, a generally straight radial portion 11, an arcuate portion 12, and an outer tab 13. The angular distance between the inner and outer tabs of a winding segment is approximately equal to the distance between adjacent pole centers of the associated magnetic pole structure. In the completed stamping the winding segments remain attached to the surrounding metal via the inner and outer tabs 10 and 13 respectively. The stamping is provided with various apertures 14 which facilitate the assembly operations and provide registry when the stampings are aligned. As illustrated in FIG- URE 2, a two layer wave type armature is assembled using a pair of these stampings 20 and 21. It should be noted that the two stampings have identical configurations but that one stamping is reversed over with respect to the other, or in other words, one stamping is rotated about an axis in the plane of the stamping. As a result, when the stampings are aligned as shown in FIG- URE 2, the arcuate portions of the winding segments in stamping 20 extend from the outer tab in a clockwise direction whereas the arcuate portions of the winding segments in stamping 21 extend from the outer tabs in a counterclockwise direction.

When the stampings are brought together to form the armature it is important to electrically insulate the winding segments in one array or stamping from the winding segments in the other array or stamping. This is conveniently accomplished by coating at least one inner surface of one stamping with a dielectric material such as a high temperature insulating varnish. More reliable insulation is achieved by applying coatings 18 and 19 to the inner surfaces of both stampings 20 and 21, resspectively, as shown in FIGURE 2. In actual production it may be simplest to dip the entire stamping thereby coating both sides in which case the coating is thereafter abraded from one of the external surfaces of the completed armature to provide a commutating surface. When the varnish has dried to provide an insulating layer the two stampings are brought together as shown in FIG- URE 3. The winding segments of the two stampings can then be bonded at their intersections by a suitable adhesive although in many cases the electrical connections between the inner and outer tabs (described hereinafter) will suffice without additional bonding.

The stampings are brought together to form a sandwich, as indicated in FIGURE 3 including, from top to bottom, stamping 20, insulating coating 18, the bonding adhesive 17, insulating coating 19 and stamping 21. The positions of the stampings are adjusted so that the inner and outer tabs come into alignment. Next, the central portions of the stampings are blanked out to free the ends of the individual inner tabs 10. Adjacent tabs in the upper and lower stampings are then welded together to form the inner bridging connections between the winding segments.

The excess material surrounding the conductor segments is next removed by a suitable blanking operation and the adjacent outer tabs in the two stampings are then welded together by similar process to form the outer bridging connections. The completed armature structure appears as shown in FIGURES 4 and 5.

As can best be seen in FIGURE 4, radial winding segment 30 from stamping 20 including its inner tab a, straight radial portion 11a, arcuate portion 12a and outer tab 13a and located in the upper layer is joined to winding segment 31 from the other stamping including its outer tab 13b, arcuate portion 12b, straight portion 11b and inner tab 10b located in the lower layer. These winding segments are joined by the bridging connection formed by tabs 13a and 13b and when joined form an armature turn. The spacing between the radial portions of the winding segments of an armature turn is approximately the same as the'spacing between pole centers of the associated magnetic pole structure. In an eight pole machine, for example, an armature turn spans approximately 90. Inner tab 10b is connected to the beginning of the next armature turn and four such successive armature turns make up an armature loop which spans slightly less than 360. The actual span of an armature loop is selected so that the end of the armature loop is at the proper point for the beginning of the adjacent armature loop and therefore the winding progresses with successive armature loops being slightly clockwise with respect to the preceding one. The armature winding is therefore evenly spaced and evenutally returns to the starting point to thereby provide a closed winding.

FIGURE 4A shows an enlarged section of the completed armature and clearly illustrates the ventilating passages 32 passing through the armature. Preferably the winding segments are skewed, i.e. not exactly radial, to thereby increase the number of intersections between the winding segments of the adjacent layers to thereby improve structural integrity.

FIGURE 4B shows an enlarged cross section of the completed armature which includes, from left to right, a winding segment 31 of one layer, the insulating coating 19 therein, the bonding adhesive 17 between winding segments, the insulating coatings 18 and the winding segment 30 in the other layer. The winding segments are joined by bridging connections 33 joining the outer tabs 13 and the bridging connections 34 joining the inner tabs 10. In some cases, these bridging connections will provide sutficient structural integrity without any adhesive bonding between the winding segments, and hence, in these circumstances, the bonding step can be eliminated from the production process.

An alternative technique for insulating and joining the winding segments in the two adjacent layers would be to use an adhesive including solid particles thereon. The adhesive might typically consist of a polyvinyl butyral modified phenolic or epoxy resin and the solid particles suspended in the adhesive can be glass micro-beads or alumina ceramic powder. The solid particles act as spacers to prevent any physical or electrical contact between winding segments while the adhesive physically bonds the'winding segments at their intersections. This alternate technique has the advantages of eliminating one step in the process (actually combines the separate coating and bonding steps into a single step) and it eliminates the drying time required for the insulating coating.

The completed motor assembly is shown in FIGURE 5 and includes a housing 40 having two similar members each including a circular base plate and an integral cylindrical portion extending from the periphery of the base plate. The illustrative motor is an eight pole machine and therefore eight cylindrical slugs 41 of an aluminumnickel-cobalt alloy material such as Alnico are secured to one of the base plates 42. These magnetic slugs are evenly distributed to form an annular array of pole faces and are each secured to the base plate by means of an adhesive such as epoxy cement. The magnetic slugs are magnetized to provide pole faces of alternating north and south magnetic polarities. An iron ring 43 is positioned directly opposite the annular array of pole faces to complete the magnetic path between adjacent pole faces and to provide a working air gap between the ring and the magnetic slugs which accommodates the armature winding.

The armature is mounted on a shaft 44 provided with an increased diameter portion 45 positioned between a pair of ball bearings 46 to prevent axial movement. The bearings are centrally mounted within suitable openings in the base plates. The armature 47, constructed in the manner illustrated in FIGURES l-4, is clamped between a pair of flanges 48 and 49 of a hub structure which are rigidly secured to shaft 44. Dielectric spacers 50 are positioned to insulate the armature winding from the hub structure.

Each of the brush holders 51 includes an insulated bushing 52 having an annular shoulder at one end so that the bushing can conveniently be inserted through a suitable opening in one of the base plates. A conductive metallic sleeve 53 is secured within the bushing and is dimensioned to accommodate a rectangular brush 54. The brush is urged toward the armature by means of a compression spring 55 located between the brush and an insulated cap 56 thread-ed on to the end of sleeve 53 which extends beyond the end of bushing 52. The electrical leads are attached to conductive sleeves 53 and the electrical circuit to the winding segments is completed via sleeves 53 and brushes 54. Flange 49 preferably has suflicient diameter to provide structural back-ing for the armature opposite the brushes. The number of brushes and the position relative to the pole faces depends upon the armature winding configuration and the current carrying requirements of the brushes.

While ony a few illustrative embodiments have been described in detail, it should be obvious that there are numerous variations within the scope of this invention.

The invention is more particularly defined in the appended claims.

What is claimed is:

1. An armature for an electrical rotary machine having a multiple stator comprising a plurality of annular arrays of winding segments lying in adjacent parallel planes, each of said winding segments extending in a generally radial direction;

a generally radially extending space between each adjacent pair of radially extending winding segments of an annular array, each such space being sufficient to provide ventilation;

bridging connections for interconnecting said winding segments to form armature turns in at least one series circuit with successive winding segments being in different ones of said arrays and being spaced apart approximately in accordance with the distance between adjacent pole centers of the associated stator a coating on at least one side of each of said annular structure;

a coating on at least one side of each of said annular arrays for electrically insulating winding segments in one of said arrays from winding segments in ad jacent arrays at their intersection, at least one external side of one of said annular arrays being uncoated to provide a commutator surface; and

ventilating passages including said radially extending spaces, said ventilating passages passing through said armature between said winding segments.

2. An armature for an electrical rotary machine having a multiple stator comprising a plurality of annular arrays of winding segments lying in adjacent parallel planes, each of said winding segments extending in a generally radial direction;

a generally radially extending space between each adjacent pair of radially extending winding segments of an annular array, each such space being suflicient to provide ventilation;

bridging connections for interconnecting said winding segments to form armature turns in at least one series circuit with successive winding segments being in different ones of said arrays and being spaced apart approximately in accordance with the distance between adjacent pole centers of the associated stator structure;

electrically insulating means for physically bond-ing said winding segments in said separate arrays only at their intersections to leave ventiliating passages through the armature between said individual winding segments, said ventilating passages including said radiall-y extending spaces.

3. An armature in accordance with claim 2 wherein said winding segments are at least partially coated with an insulating medium to provide electrical insulation at.

said intersections.

4. An armature in accordance with claim 3 wherein said coated winding segments are physically bonded at said intersections by an adhesive.

5. An armature in accordance with claim 2 wherein said electrically insulating means is an adhesive including 6 solid particles therein for maintaining an insulating separation between said winding segments at their intersections. '6. An armature for an electrical rotary machine having a multipole stator comprising a plurality of annular arrays of uniformly spaced wind- 6 ing segments lying in adjacent parallel planes, each winding segment spanning an angular distance approximately equal to the distance between adjacent pole centers and extending in a generally radial direction but skewed relative to radii passing through the armature axis;

a generally radially extending space between each adjacent pair of radially extending winding segments of an annular array, each such space sufiicient to provide ventilation;

bridging connections for interconnecting said winding segments to form armature turns in at least one series circuit with successive winding segments being in different ones of said arrays, each armature turn including a pair of winding segments;

said winding segments of the different arrays being aligned to provide intersections and ventilating passages through said armature and between said segments, said ventilating passages including said radially extending spaces; and

means providing electrical insulation between adjacent winding segments at said intersections.

7. An electrical rotary machine comprising a magnetic stator structure providing, across and annular air gap, an array of magnetic poles of alternating magnetic polarity;

a plurality of annular arrays of winding segments 1ying in parallel planes in said air gap adjacent said magnetic poles, each of said winding segments extending in a generally radial direction;

a generally radially extending space between each adjacent pair of radially extending winding segments of an annular array, each such space being sufiicient to provide ventilation;

bridging connections for interconnecting the ends of said winding segments to form a uniform closed armature winding with successive winding segments being in different ones of said arrays and being spaced apart approximately in accordance with the distance between adjacent pole centers of said stator structure;

said winding segments being arranged to provide intersections within said air gap between winding segments of the different arrays and to provide ventilating pas-sages through the armature between winding segments, said ventilating passages including said radially extending spaces;

means insulating winding segments from adjacent winding segments at said intersections; and

commutator means electrically coupled to said armaature winding.

8. An electrical machine in accordance with claim 7 wherein said winding segments are physically bonded at said intersections.

References Cited U.S. Cl. X.Rl 

